The present invention relates to an apparatus for steering a joystick of a ship for use in steering of the working ship having a plurality of propelling equipment such as an anchor handling tag supply vessel.
Hitherto, the working ship which is known as an anchor handling tag supply vessel and used in material handling to the oil digging rig is ordinarily equipped with: two rudders and two variable pitch propellers which are provided on the side of the stern; and further a bow thrustor, provided on the side of the bow, for obtaining the thrusts in the lateral direction perpendicular to the progressing direction of ship. These five thrust equipment are respectively controlled by independent levers.
The works which are required for such a working ship include: supply of material to the oil digging rig at a location near the rig; loading and unloading of material by the crane of the rig; anchor handling to move and moor the rig; and the like. For these works, in the disturbance such as wind, tidal current, and the like, it is required to perform the delicate steering operations of the ship at a low speed at the current position such as turn, lateral movement, inclined sailing, holding of the specific point at sea, holding of the bow azimuth, and the like.
To satisfy these requirements, the shipbuilder considers the performances of five thrust equipment provided for the ship and adjusts the respective control levers in accordance with the situation and continues the works for a long period of time. Therefore, such works become fairly large mental and physical burdens to the skilled shipbuilder as well.
The inventors of the present invention has been progressing the development of what is called a joystick control system which can operate five thrust equipment by the operation of a single joystick lever. A conventional joystick apparatus as an input apparatus for use in such a system generally has the structure such that a rotation angle detector is provided for each of X, Y, and Z axes adapted to rotate in association with the operation of the joystick lever. Further, there has been known the apparatus such that the rotation angles around two X and Y axes due to the joystick are detected and another knob separately provided is operated with regard to the Z axis.
However, in such a conventional apparatus in which the rotation angles around three axes due to the operation of the joystick lever are detected, the gimbal structure having three angle detectors is needed, so that there are the following problems. The structure of the apparatus is complicated and the movable portion enlarges, so that it is difficult to realize the small-sized and light-weighted apparatus. On the other hand, with respect to the Z axis, in the case of the apparatus which needs to operate the knob, two operating portions exist, so that it is troublesome to operate them upon steering of the ship while observing the outside condition and the monitor display.